www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850
www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12860
Solar water heaters have been replacing gas water heaters over the past ten years at a rapid pace. Consumer interest in them is not solely for the tax credits, but also for their economic payback with cheaper bills and startup costs.
The pros and cons for gas and solar water heaters are lengthy so there are a few things one needs to know when weighing the idea of solar. Solar powered heaters come in many different forms but typically consist of a collector and a heater.
There are three different types of collectors:
-Flat Plate Collector- This collector is an insulated and weatherproof box with a dark absorber plate underneath glass or plastic covers. They are similar to those used to heat swimming pools.
-Integral Collector Store Systems-These are also known as ICS or batch systems. They are made up of black storage tanks and tubes in a similar insulated box. Cold water passes through the solar collector first, heating up the water just a little, and then proceeds on to the backup water heater. This keeps a consistent source of hot water, and is more reliable. However, they are not good in cold climates as the tubes could freeze.
-Evacuated Tube Solar Collectors- These are made up of rows of clear glass tubes. Each tube has a metal absorber tubs which absorbs solar energy but inhibits radiant heat loss.
There are two types of active solar water heating systems:
-Direct Circulation Systems- pumps circulate household water through the collectors and into the home. This does not work in freezing climates.
-Indirect Circulation Systems- The pumps use a heat-transfer liquid and a heat exchanger. They are better for freezing temperatures.
Passive solar water heating systems tend to be less expensive and more reliable than active systems, but they are less efficient as well.
-Integral Collector Storage Passive Systems- This systems does not work well in freezing climates. They are very efficient with daytime and nighttime hot-water.
-Thermosyphon Systems- With this system, water flows through the system when warm water rises as cooler water sinks. These are less expensive than the previously mentioned passive system. The storage tank is heavy, however, so the contractor has to pay special attention to the roof of the home.
After learning a little bit about how the solar water heater systems work, it is important to weigh the pros and cons.
These systems range from $1,500 to $3,500. Gas systems cost between $150 and $450. This difference in price is significant and one must also consider the installation costs of the solar system which can run up to $2,000 plus regular maintenance costs.
Having explained costs, the solar systems last around the same as the gas systems yet they’re payback happens in four to eight years when you weigh gas vs. electrical bills. This means that within four to eight years, it is as though you are not paying for hot water anymore.
Another bonus can be found in tax credits. For any system installed after December 31, 2008, there is no maximum to the possible tax credit. Energy Star also has their own line of solar water heaters, which provides a full line of commercial and domestic energy efficient products.
Solar water heaters are not all mighty, however, and do have their fair share of negatives. For starters, the maximum water temperature that can be reached is lower than that of a regular on-demand system and the heating process tends to be slower.
The reliance on weather also provides a hurdle as the unit needs sunlight to produce the hot water. Many of the newer systems have a backup system to negate this.
One of the biggest concerns is their water storage tank. These can get quite large and if a contractor does not install them properly, there is risk of the roof getting damaged, as well as the interior of the home.
All of the negative aside, solar powered water heaters prove to be an economically feasible and friendly option for homeowners who plan to stay in the same home for an extended period of time and reap the benefits of the payback.
Miami Green Homes 
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